Overview
The ZF 4143.020.202 2 HL 270 Hydrostatic Drive Assembly is a complete, factory-sealed unit engineered for precise power transmission in heavy-duty industrial drivelines. This assembly integrates the pump and motor into a single, robust package, converting hydraulic pressure into smooth, variable-speed mechanical output. It sits at the core of the transmission system, directly managing torque flow to the final drive. The SKU 4143.020.202 designates a fully assembled unit, ready for direct replacement in ZF HL 100 and HL 270 series applications. For proper installation, ensure the mating 4143101046 HOUSING and the 4143301055 HOUSING are free of debris, and that the 0631329135 SPRING PIN is correctly aligned to secure the assembly.
Symptoms of Failure
- Erratic or jerky vehicle movement: When the hydrostatic drive assembly wears, internal piston or swashplate damage causes uneven fluid flow, leading to sudden lurches or hesitation during acceleration.
- Persistent oil leaks from the drive housing: Worn seals or a cracked 4143298040 CASE allow hydraulic fluid to escape, often pooling beneath the transmission or dripping from the unit’s flange.
- Loss of power under load: Internal bypassing due to worn valve plates or cylinder block faces reduces system pressure, causing the vehicle to struggle when climbing or carrying heavy loads.
- Excessive operating noise or whining: Cavitation or metal-to-metal contact within the rotating group produces a high-pitched whine or grinding sound, indicating imminent failure.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4143.020.202 |
| Assembly Type | 2 HL 270 Hydrostatic Drive (Complete Unit) |
| Displacement | 270 cc/rev (estimated) |
| Maximum Operating Pressure | 420 bar (6,100 psi) |
| Weight | Approx. 85 kg (187 lbs) |
| Housing Material | High-strength cast iron |
| OEM Reference | ZF 4143.020.202 |
| Mounting Flange | SAE B or C (verify application) |
Compatibility
This hydrostatic drive assembly is designed for ZF transmissions in the HL 100 and HL 270 series. It is commonly used in models such as the WG180, WG200, and WG250, as well as the WG120 series where a 270 cc displacement is specified. Always cross-reference your transmission serial number to confirm fitment. The unit also integrates with the 4WG200 and 6WG250 power shift transmissions used in construction and agricultural machinery.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101046 | HOUSING | Encloses the drive assembly, providing structural support and fluid channels. |
| 4143301055 | HOUSING | Secondary housing for bearing and seal retention. |
| 4143298040 | CASE | Outer casing protecting internal rotating components. |
| 0631329135 | SPRING PIN | Locks housing alignment during assembly. |
| 0501214034 | SEALING CAP | Prevents fluid ingress at unused ports. |
| 0636101024 | CAP SCREW | Fastens housing sections together. |
| 4475280099 | SCREW PLUG | Seals hydraulic test points. |
| 0634303266 | O-RING | Provides static seal between mating surfaces. |
| 0501200072 | VENT VALVE | Relieves internal pressure to prevent seal damage. |
| 0501217673 | LUBRICATING NIPPLE | Grease fitting for external bearing lubrication. |
